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North Cascades National Park Nature

North Cascades National Park

Nature and Science

Thrust up from the ocean floor in a tectonic collision millions of years ago, the North Cascades have been chiseled by glaciers into a jagged mountain realm full of sharp, stony peaks, deep valleys and long lakes. The North Cascades are part of a mountain range that stretches from Canada to California along the pacific crest. The park is unique as the most heavily glaciated area in the United States outside of Alaska. More than 300 glaciers are at work year-round in the park slowly etching away at the landscape like patient master sculptors.

These mountains are home to a diverse host of flora and fauna. The lower elevations are forested with fir, hemlock, pine and cedar, while high amongst the snowfields sprawling subalpine meadows teem with wildflowers. The forests, fields, rivers and streams of this enchanted mountain realm are home to an exceptional amount of biodiversity.


Plant life in the North Cascades is extremely varied, reflecting differences in rock and soil types, exposure, slope, elevation, and rainfall. Eight distinctive life zones support thousands of different plant species in the North Cascades greater ecosystem. No other US National Park surpasses North Cascades National Park in the number of plant species recorded. Over 1,627 vascular plant species have been identified, and estimates of non-vascular and fungal species could more than double this number for total plant species in the North Cascades. Some of these plants are threatened or endangered, and changes such as air pollution and global warming might affect their survival. Other threats include invasive non-native plants that are referred to as exotic species. Exotic species are capable of displacing native species and changing biotic communities. Resource managers at North Cascades National Park are taking action to reduce this threat by removing these invasive plants. This can be particularly difficult because these plants utilize trails, waterways, wind, and roads to colonize the area. Restoration of habitats changed by human activity has been a priority since the park was established in 1968. As leaders in developing methods of revegetation in the National Park Service, the plant propagation crew has grown thousands of native plants from seeds and cuttings. Taken from areas adjacent to damaged sites, these seeds and cuttings are later returned as young plants to restore campsites and trampled areas of the park.

Trees and Shrubs

Conifers - the Cone Bearers - dominate the forests of the North Cascades. They span the elevation ranges from sea level to the alpine zone, sheltering the low valleys and clinging to the thin mineral soils of the high peaks.

The conifers are often referred to as evergreens because of their characteristic needle or scale-like leaves that persist throughout the year. Yet, two species of larch are deciduous - dropping their needle leaves in the fall after turning a beautiful soft shade of gold.

In the North Cascades conifers define the major forest types, but adding to their complexity are many species of deciduous broad-leaved trees. Species of maple, poplar, and alder grow in the natural openings caused by disturbances to the upper canopy. This happens when large trees are blown over by wind or die of disease. Broad-leaved trees also grow along the edges of streams and rivers where there is more available light.

Woody shrubs, both coniferous and deciduous, grow in the understory of these forests providing shelter and food for wildlife. Many birds such as the rufous hummingbird also use shrubs for nesting. Shrubs are also important along stream corridors where their shade helps to keep water temperatures from getting too high for fish, particularly salmon, and other aquatic fauna.

What is the difference between a shrub and a tree?

Generally, trees are over 20 feet tall and have trunks more than 2 inches in diameter at 4.5 feet about the ground. Shrubs are smaller than trees and often have many small, woody, bark covered stems rising from the base.


Wildflowers can be found everywhere in the North Cascades. They occur across the entire range of habitat types from wet hillside seeps and moist, shady forest floors to dry east-side slopes and exposed alpine ridges.

Flowers are remarkably diverse. They can bear a single flower or hundreds of small ones; they can be simple or ornate, growing alone among ancient hemlocks or as stunning displays in open alpine meadows.

Many of the wildflowers in the North Cascades will be familiar due to their wide spread distribution, but a few will be found nowhere else in the world. Many wildflowers are partial to one side of the Cascade ridge or the other, the moist west side or the dry east side, which can lead to a dramatic change in scenery and habitat types.

The great differences in elevation, exposure, and precipitation that exist in the North Cascades promote a range of flowering times. Some plants are flowering by late February and early March in the low elevation forests, and as late as August and early September in the alpine zone. While most of our flowers are insect or wind pollinated, those blooming during the relatively warmer days of April and May, such as salmonberry, Indian plum, and red-flowering currant will be visited by hummingbirds returning to breed.


Ferns thrive in the low light and high moisture forests of the North Cascades. Sword, deer, licorice, lace, parsley, maidenhair, bracken, lady, oak and wood ferns dapple the forest floor.

These ancient plants have been living on this planet for more than 300 million years. Ferns dominated the plant world until flowering plants emerged during the age of dinosaurs. They have internal tubes for transporting water and nutrients, without which, a plant cannot grow more than a few inches tall. Ferns have two distinguishing characteristics: they reproduce by spores (visible in small clusters called sori on the underside of leaves) and their leaves unroll from base to tip as they mature (resulting in a fiddlehead appearance).

What image of the Pacific Northwest would be complete without the forest floor covered in lush, green ferns? As you walk through the woods of the North Cascades you will discover that in moist places ferns dominate the understory. Walking amongst the fronds, what you are actually viewing are the leaves of the plant, which grow out of horizontal, underground stems called rhizomes.


Grass and grass-like plants include the true grasses (family Poaceae), rushes (family Juncaceae) and sedges (family Cyperaceae).

These plants all have tiny, simple flowers and are wind pollinated. They occupy a variety of habitats from low elevation wetlands to dry wind blown mountain ridges.

Within the North Cascades, true grasses include approximately 150 species half of which are native. Of the species that are non-native, the worst invader is reed canary grass ( Phalaris arundinaceae ). It can be found in wetlands, on lakeshores, and river edges.

Rushes and sedges are invaluable for their ability to stabilize stream banks, filter sediments, and along with many true grasses they provide habitat and food for numerous animals and other organisms.


Common in the North Cascades, lichens are unique, composite life forms created when fungi enclose algae in mutualistic symbiosis. In such a relationship both organisms should benefit, however, many lichenologists believe the partnership may actually be more beneficial to the fungus than the algae. Algae have the ability to create food through photosynthesis but are vulnerable to the elements. Fungi, which are not green for lack of chlorophyll, are unable to photosynthesize their own food. When alone, fungi are usually found in the form of mold, mildew or mushrooms that play many beneficial roles in decomposition. They are also found acting as symbiotic partners of other plants in the forest. Together as lichens, algae and fungi offer something to the other: algae provide carbohydrates and fungi provide protection. Lichens exploit habitats where fungi and algae could not survive independently. As a result, the forest in the North Cascades is literally covered with lichens. They are on trees, talus slopes, and even old buildings. They display a rich diversity of forms, which to many observers is the beauty of lichens. Lungwort ( Lobaria pulmonaria ) looks like a rubbery piece of lettuce and is easy to find scattered on the ground, especially after a windstorm has knocked it out of the canopy above. Old-man's-beard ( Alectoria sarmentosa ) looks like green, stringy hair hanging from tree branches. Lichens provide food for animals such as flying squirrels and material for birds' nests. Lichens are essential nitrogen fixers in forest floor soils. Sensitive to pollution, lichens are studied by park scientists to measure pollutants and aging geologic exposure.

Mosses and Liverworts

Not so long ago, ancient forests filled the valleys of the North Cascades. Curving corridors still drip with lush dark green tiny plants. Mysterious, shaggy plants of primitive origin cover the forest floor and drape from branches, as if dripping like the incessant rainfall. Soft carpets cover every branch, nurse log, and rock. They cushion and replenish forest soils.

Tiny moss forests seem like a microcosm of the ancient forest. Change, dependence on clean air and water, and unique phases of life determine their existence.

These cryptogams are like 'hidden puzzles' of untold variety. They are among the most abundant (hundreds of species in the North Cascades) and least understood plants on earth. Lacking roots and the vascular system common to seed plants, they rely on nutrients dissolved in the damp, wet air. Each fall and spring lush carpets expand, grow and reproduce as they literally suck in and reserve moisture during the wet times of the year. During the coldest and driest times, mosses and liverworts can let go of their moisture and dry out without dying. They do this during the frozen winter and dry hot summer. Surviving with little sunlight or contact with soil, these amazing plants remind us of ancient times and forests that will continue to cycle through time.

Mushrooms and Other Fungi

Estimates range from 800 to 2,000 species of fungi. However, not to put to fine a point on it, a mushroom is not actually a fungus in much the same way that an apple is not an apple tree. Mushrooms are actually the fruiting bodies of fungi, which grow in extensive networks in the ground, rotting log or other nutrient rich medium. To call a mushroom a fruit, though, is also not entirely accurate. Mushrooms and fungi have proven so difficult to categorize that a growing number of scientists hardly consider them part of the plant kingdom at all.

The visible part of a fungus;the mushroom;is only the tip of a very interesting iceberg. Beneath the surface may grow a fungal system as extensive and old as the most ancient of trees. Like trees, fungi often grow in rings, which expand each year. The visible representation of this is what is called a "fairy ring". A fairy ring is a ring of mushrooms growing out of the ground that represents the outer boundary of the subterranean fungus. The largest fairy rings are more than 600 ft in diameter putting those fungal systems at an age five to seven centuries old.

For all we've learned about them, less is known about fungi and their ecological role than that of plants and animals even though they play a key role in the forest community. Fungi decompose organic material releasing nutrients into the ecosystem and often have hidden connections to the plants around them. More than 90 percent of vascular plants form underground links with fungi called mycorrhizae. This symbiotic exchange benefits both plant and fungus in germination and nutrient gathering.

Their prevalence, symbiotic links with nearly every species of plant and sensitivity to air quality make fungi of great ecological importance. Accordingly, the park has developed a photographic inventory of fungi to better monitor them within the park.

Note: Mushroom collecting is prohibited within North Cascades National Park Service Complex. Check at ranger stations for more information.


Amidst the high peaks, deep forests and cold rivers for which the park is renowned wetlands, marshes and swamps may be the last thing people think of when they visit. Although they are not the most prominent aspects of the park ecosystem, they are one of the most important. They prepare the ground from which, in time, will spring forth an ancient forest. Wetlands also provide perfect habitat for many amphibians, invertebrates and aquatic plants.

Some of the most outstanding wetlands in the park are nestled along the lower stretches of the Chilliwack River. The area is a magnificent expanse of relatively inaccessible and pristine wilderness, which has been recommended for designation as a Research Natural Area. Here, near the Canadian border, is located one of the largest wetlands in the park, boasting forested, scrub/shrub, emergent and open water wetlands. As with all ecosystems, this environment is dependent on the plants and creatures that dwell there.

Much of the wetland is maintained by a colony of beavers that dam the streams with freshly cut alder boughs, stream debris and packed mud. The standing water and the animal and plant activity that occurs within it saturate the ground with nutrients preparing it for the forests of future generations. The wetland is dependent on the beaver colony just as the beaver colony is dependent on the wetland and future old-growth forests are dependent on them both. The wetland environment provides us with yet another example of how all things in nature are interconnected, even the wetlands that so often go overlooked.

Nonnative Species

The North Cascades are witness to an epic struggle. On one side are native plants such as vine maple, bracken fern, and thimbleberry which have made their home in this ecosystem for thousands of years, adapting to thrive in this unique climate and terrain. On the other side are non-native plants such as English ivy, scotch broom, and spotted knapweed which have settled into this ecosystem within the last two hundred years. The non-natives are looking to displace the natives and claim the habitat as their own.

Many non-native plants were introduced to the North Cascades ecosystem by humans seeking to beautify areas or to revegetate disturbed land resulting from construction projects. Others were introduced by accident, brought in as seeds attached to vehicles, animals, and cargo. Whether valued for their beauty or for their rapid growth, these non-natives have been successful in their new environment and threaten to completely displace the ecosystem's original inhabitants.

What will the future look like? The natives will reclaim the habitat lost to the non-natives. This is, if resource managers at North Cascades National Park Complex get their way. Non-native species are sought out and eradicated through a variety of techniques. Some plants are removed by hand; others are attacked by biological controls, insects that eat plant-specific seeds. Even herbicides are being used where necessary as a last resort to give the natives the upper hand in their struggle against the non-natives.

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